The present invention relates to a battery plate stacker, and more specifically relates to a battery plate stacker including a wire flattener module and a method of operation therefor.
The context for the present invention deals with battery plate stackers. However, prior to discussing the specific operation of a battery plate stacker, it is necessary to first understand the general steps involved in the production of batteries. In its simplest form, a battery comprises a plurality of positive and negative plates stacked in alternating fashion, and having a separator material interspersed between them. The battery plates are retained in a battery container, which also contains electrolytic fluid. The chemical interaction between the electrolytic fluid and the battery plates generates electrical current, which is drawn out through the battery terminals.
For example, U.S. Pat. No. 5,384,217 discloses one process for producing battery plates. This process for making such plates includes an initial step of melting hot lead in a furnace, followed by a step of feeding molten lead alloy to a strip caster. Trim from the caster is recycled to the furnace. The strip is coiled on a winder, and coils of lead alloy strip are stored for later use.
To form a battery grid, the coil is unwound and the free end is fed through an expander that cuts, slits, and stretches a strip of coil to form a mesh-like wire grid.
U.S. Pat. Nos. 4,315,356 and 4,291,443 disclose expanders used in the production of wire grids for use in making negative expanded metal battery plates. The expanded strip or wire grid is then pasted by a conventional paster, and fed to a divider where the strip is cut. Plates cut from the strip are next flattened in order to smooth out any uneven regions of battery plate paste. From here, the plates pass on a conveyor through an oven for flash-drying, and are then stacked for later use. Flash-drying is performed using an open gas flame or an oven. After flash drying, the battery plates undergo a chemical treatment, well known to those skilled in the art.
Following chemical treatment of the battery plates, negative expanded metal plates are delivered to a stacker operator. Stacks of the negative expanded metal plates are then manually prepared by loosening the bonding, which results from the chemical set process, between adjacent plates. Next, the plates are inspected for visible damage prior to loading into the battery plate stacker.
Battery plates stackers, such as those manufactured by Tekmax of Oregon, are well known to those skilled in the battery arts. Such battery plate stackers generally include means for feeding the negative and the positive battery plates into the battery plate stacker, an enveloping module for wrapping negative expanded metal battery plates with a separator material, a conveyor for moving the negative and positive battery plates, and a module for stacking the negative and positive plates together.
In general, battery plate stackers are operated as follows. First, negative expanded metal battery plates are placed into the negative plate feeder, while positive battery plates are placed in a separate feeder. Individual negative expanded metal battery plates are separated from their stack and picked up by well known means, such as with a vacuum-type system, for moving the plates onto a carrier. Once on the plate stackers' carrier, the negative expanded metal battery plates are transferred through the plate stacker to the enveloping module. Here, the negative expanded metal battery plates are enveloped in a separator material. Additionally, a set of meshed wheels seal the separator material around the negative expanded metal battery plate, with the lug side of the plate open. The side of the negative expanded metal battery plate located opposite the lug side is flush against a crease in the separator material. At present, it is common during this crimping process that bent, exposed wires of the negative expanded metal battery plates' wire grid will pierce the separator material.
Next, separator-enveloped negative expanded metal battery plates exit the enveloping module and enter the stacking module. The stacker module will prepare a series of alternating negative and positive plates. Those skilled in the art understand that a single enveloped negative plate matched with a single positive plate is called a "chapter," while a plurality of stacked chapters is typically referred to as a "book."
The process of stacking the positive plates onto the negative plates is accomplished with a positive plate feeder that stacks a positive plate onto a separator-enveloped negative expanded metal battery plate as it is conveyed past the positive battery plate feeder. From this point, the book of battery plates are transferred into a cast-on strap machine. The cast-on strap machine will cast a strap to join all negative plate lugs, and a separate strap to join all positive plate lugs in the book. The battery plate book, now with straps connected, is placed into the battery case.
As the process for producing batteries is so lengthy and complex, and the present methodology for detecting electrical shorts occurs only after the battery has been substantially assembled, a need exists to eliminate the source of electrical shorts altogether. The present invention provides an improved battery plate stacker including a wire flattener module that substantially eliminates the occurrence of electrical shorts resulting from piercing the separator material with exposed wires from the negative expanded metal battery plate wire grid.